1. Field of the Invention
The invention relates to a setting device for a motor vehicle with a mechanically adjustable component and a process for operating the setting device.
2. Description of the Related Art
It is typical in automobiles to couple a setting element, designed, for example, as a foot lever, with a sensor, which detects the angular position of the lever. The position signal of the lever is adjusted after installation into the automobile, in that in a stop position of the foot lever an auxiliary signal is set by way of an external signal input, or in that the position of the sensor itself is adjusted mechanically. The signal level, pending at the sensor in this instant, is then stored as the output signal and subtracted or compared in a subsequent operation. The reliability of the process can hardly be guaranteed according to automobile aspects. It is possible during subsequent operation of the motor vehicle that the geometry of the lever unit changes, for example, due to increasing bearing play, by means of deformations or in the event of a repair. Even the sensor, designed, for example, as a rotary potentiometer or Hall sensor, can change its characteristics through wear and contamination, for example, with ice particles. The properties of the electronic components will also vary in operation due to aging and environmental influences, a factor that can result automatically in a signal drift.
Conventional adaptive learning systems cannot be applied here, since the actuating profiles of the signals are a function of both the driver and the traffic situation, such as an uncontrolled long dwell period in a specific position. Furthermore, known algorithms cannot measure the short-term zero point changes, such as those that occur, for example, after a repair.
The DE 3612904 A discloses a process for the tolerance compensation of a position sensor signal, wherein the neutral position of the component is monitored during the operation of the motor vehicle. In this respect the measured values of an upper or a bottom stop are stored. Should one of these end values be exceeded during operation, the new measured value is stored as the new end value. This feature has the drawback that an actual drift of the neutral position toward the medium range cannot be detected at all.
The invention is based on the problem of eliminating the adjustment cost and increasing the functional reliability.